Special Conditions: Chelton Flight Systems, Inc.; Various Airplane Models; Protection of Systems for High Intensity Radiated Fields (HIRF).

The FAA published a document in the Federal Register on August 30, 2002 (Volume 67, Number 169) regarding Special Condition 23-127-SC for Chelton Flight Systems, Various Airplane Models; Protection of Systems for High Intensity Radiated Fields (HIRF). This amendment is being published to add several airplane models to the existing special condition to cover current and future amendments to the Approved Model List (AML) STC. These special conditions address HIRF certification requirements for digital systems not addressed by the current regulations. See the attached AML for the airplanes that are added by this amendment. These airplanes, as modified by Chelton Flight Systems, will have a novel or unusual design feature(s) associated with the installation of an electronic flight instrument system. These special conditions address the protection of these systems from the effects of high intensity radiated field (HIRF) environments. The applicable airworthiness regulations do not contain adequate or appropriate safety standards for this design feature. These special conditions contain the additional safety standards that the Administrator considers necessary to establish a level of safety equivalent to that established by the existing airworthiness standards.